Dental compositions having a sticky matrix material for treating sensitive teeth

ABSTRACT

The present invention discloses sticky dental compositions and methods for treating sensitive teeth. For maximum comfort, an improved dental tray that is thin-walled, flexible and lightweight is used to hold the dental composition adjacent the desired tooth surfaces. The dental compositions include a sticky matrix material into which is dispersed a desensitizing agent such as KNO 3  and other optional dental agents. The matrix material preferably includes carboxypolymethylene that has been partially neutralized with a base to reduce etching of the enamel. The carboxypolymethylene adds a unique stickiness to the dental composition which helps to adhere and retain the soft tray material against the patient&#39;s teeth.

BACKGROUND

1. Related Applications

This application is a continuation-in-part of U.S. application Ser. No.08/722,549, filed Sep. 27, 1996, now U.S. Pat. No. 5,725,843, which is acontinuation of application Ser. No. 08/378,315, filed Jan. 25, 1995,now U.S. Pat. No. 5,770,182 which is a continuation of application Ser.No. 08/099,247, filed Jul. 28, 1993, now abandoned, which is acontinuation of application Ser. No. 07/985,700, filed Dec. 2, 1992, nowabandoned, which is a continuation of application Ser. No. 07/718,210,filed Jun. 20, 1991, now abandoned, which is a divisional of applicationSer. No. 07/497,934, filed Mar. 22, 1990, now abandoned. For purposes ofdisclosing the present invention, the foregoing applications areincorporated here by specific reference.

2. The Field of the Invention

The present invention relates to sticky compositions and methods fortreating sensitive teeth. More particularly, the present invention isdirected to dental compositions having a sticky matrix material intowhich a desensitizing dental agent is dispersed. The novel compositionsare used in combination with a thin-walled dental tray in order toprovide prolonged treatment of a patient's teeth over extended periodsof time.

3. The Relevant Technology

Most people have experienced sensitive teeth at sometime in their lives.Tooth sensitivity is a condition in which a person feels either suddenand intermittent dental pain, or a chronic gnawing dental pain.Sensitive teeth can be an inherited condition or it can be caused bysickness, poor dental hygiene, and/or the use of certain dental agents,such as bleaching agents. For example, peroxides and other bleachingagents have been used in order to cause a whitening effect in a person'steeth. The bleaching action is thought to occur when oxygen radicalsreleased by the decomposing peroxide ions permeate into the person'senamel and attack color-causing molecules found therein.

Unfortunately, due to the existence of natural pores within a person'steeth and/or fissures between the interface between teeth and fillings,it is possible for the peroxide ions and the liberated oxygen radicalsto permeate into the pulp of a person's teeth. Since the pulp includesvery sensitive nerve endings, the aforementioned pores and/or fissuresprovide a direct conduit whereby the peroxide ions and oxygen radicalscan irritate the nerves within a person's teeth. While the teeth are notgenerally harmed by peroxide ions and oxygen radicals, they can becomeoverly sensitized over a period of time, causing pain or at leastgeneral discomfort.

In order to treat sensitive teeth, toothpastes and other dentifricesthat include desensitizing agents have been developed for topicaltreatment of sensitive teeth. In the case of toothpaste, the personsimply brushes his or her teeth with the toothpaste that includes thedesensitizing agent. Alternatively, or in conjunction with home use,desensitizing agents can be applied by a dentist during a dental visitin order to provide temporary desensitization. Unfortunately, suchdesensitizing toothpastes and other dentifrices have obvious drawbacks.

Since desensitizing agents only provide temporary relief of painful orsensitive teeth, desensitizing agents applied by the dentist willquickly wear off, leaving the patient with sensitive teeth shortlyfollowing the dental visit and long before the next scheduled visit. Onthe other hand, although a person can use a desensitizing toothpaste ona regular basis as part of his or her daily oral hygiene, the time inwhich a person typically brushes does not provide enough contact time inorder to provide the same level of pain relief that is afforded bydesensitizing treatments applied by a dentist. A person will typicallybrush for only one minute or less, which is generally an insufficientamount of time for a desensitizing agent to permeate into the poresand/or fissures within a person's teeth in a high enough concentrationin order to desensitize the teeth. Nor are toothpastes able to provide ahigh enough concentration of desensitizing agent since toothpastes bynecessity must include abrasives for cleaning the teeth, surfactants,fluoride, fillers and other agents.

More recently, dental compositions used for bleaching teeth have beendeveloped that are able to be used in conjunction with a tray configuredto fit over a person's teeth. Conventional dental trays, including thosespecifically adapted for delivering a medicament to a person's teeth aswell as mouthguards used to protect a person's teeth while playingsports, remain in place by means of mechanical pressure exerted by thedental tray onto the person's teeth. Unfortunately, the exertion ofmechanical pressure onto a person's teeth can create significantdiscomfort and cause a disincentive for continuing a tooth treatmentregimen.

For example, dental trays such as those described in U.S. Pat. No. Re34,196 to Munro are adapted to provide a liquid-tight seal over theperson's gums in order to retain a generally non-viscus bleachingcomposition against a person's teeth. Like dental trays that exertmechanical pressure onto a person's teeth, the dental trays according toMunro that exert enough pressure to create a liquid-tight seal about aperson's gums can result in significant discomfort and result indiminished desire to complete a dental treatment regimen.

As set forth in the parent applications identified above, e.g. U.S.application Ser. No. 07/497,934, the inventor has developed flexible,thin-walled dental trays that exert little or no significant mechanicalpressure on a person's teeth when in place to provide a more comfortablefit. The inventive dental trays optionally include reservoirs forproviding more of a dental composition against one or more of theperson's teeth. Furthermore, the dental tray can alternatively beconfigured to overlap a portion of the person's gums or it may betrimmed at or below the gingival margin in order to maintain the dentalcomposition away from the person's gums. In either scenario, theinventive dental trays exert little or no significant mechanicalpressure onto the person's teeth or gums so that the trays are morepleasant to use.

Unfortunately, since the comfortable dental trays exert little or nosignificant mechanical pressure onto a person's teeth or gums, thedental trays could fall from a person's teeth or otherwise be dislodged,thereby interrupting or disturbing the treatment regimen. Since neitherdesensitizing agents used in the dental office, which are non-viscousfluids, or toothpastes that include a desensitizing agent are adaptedfor use with dental trays, there has not heretofore existed a dentalcomposition for treating sensitive teeth that could be used inconjunction with the comfortable-fitting dental trays developed by theinventor.

In light of the foregoing, it will be appreciated that what is needed inthe art are improved compositions and methods for treating sensitiveteeth that could provide treatment more frequently than during dentalvisits.

Additionally, it would be a significant advancement in the art toprovide improved compositions and methods for treating sensitive teethwhich could be used frequently, but which provides more prolongedtreatment for an extended period of time compared to conventionaltoothpastes.

It would be another significant advancement in the art to providecompositions and methods for treating sensitive teeth which allow moreof the desensitizing agent to permeate into the pores and/or fissureswithin a person's teeth in order to provide greater desensitization.

It would be an additional advancement in the art to provide dentalcompositions and methods for treating sensitive teeth that could beadapted for use by disabled or semi-debilitated people who may not havethe strength, coordination, or ability to brush their teeth without theassistance of others.

It would further be an advancement in the art to provide compositionsfor treating sensitive teeth which could optionally include other dentalagents, such as antimicrobial agents or anticariogenic agents, fortreating other tooth and/or gum ailments.

Finally, it would be a further improvement in the art to providecompositions for treating sensitive teeth that were sufficiently stickyand resistant to dilution by saliva such that they had the ability toadhere and retain a flexible, thin-walled dental tray against a person'steeth, wherein the dental tray did not exert significant mechanicalpressures onto the person's teeth or gums.

Such compositions and methods for treating sensitive teeth are disclosedand claimed herein.

BRIEF SUMMARY AND OBJECTS OF THE INVENTION

The present invention is directed to sticky dental compositions thatinclude a desensitizing agent for treating sensitive teeth. The dentalcompositions include a sticky matrix material into which thedesensitizing agent and, optionally, other dental agents are dispersed.An improved dental tray that is preferably thin-walled, flexible andlightweight is preferably used to hold the dental composition adjacentto the person's tooth surfaces to be treated. The preferred dental trayshould be adapted for maximum comfort and will exert little if anysignificant mechanical pressure onto the person's teeth or gums.Accordingly, the improved dental compositions should be sufficientlysticky and resistant to dilation by saliva such that they can act as aglue and reliably adhere and retain the dental tray over the person'steeth for varying time durations.

The tooth desensitizing agent is preferably dispersed within a sticky,glue-like matrix material to form the sticky dental composition.Suitable sticky matrix materials are preferably safe for oral use, donot readily dissolve in saliva, and do not react with the toothdesensitizing agent. One currently preferred sticky matrix materialincludes carboxypolymethylene together with other suitable admixtures.The term "carboxypolymethylene" is used to denote a broad category ofpolymers, particularly copolymers of acrylic acid and polyallyl sucrose.Because carboxypolymethylene includes carboxylic acid groups ormoieties, it can be classified as a weak acid. When dispersed in water,carboxypolymethylene can have a pH as low as about 2.5.

Although water is only optionally included within the compositions ofthe present invention, since a person's mouth includes saliva, which isaqueous, it would generally be detrimental to a person's teeth to applya composition that can become acidic in the presence of saliva, sinceacids can attack tooth enamel. Accordingly, it is preferable to adjustthe pH of compositions that include carboxypolymethylene with a rangefrom about 4 to about 9, more preferably in a range from about 5 toabout 7. Because it is contemplated that the carboxypolymethylene usedin the matrix material and the compositions of the present inventionwill be neutralized to a certain extent, the term "carboxypolymethylene"shall include carboxypolymethylene polymers at any pH, whether in aneutralized, partially neutralized, or non-neutralized form.

The matrix material can include other optional components in addition tothe carboxypolymethylene in order to provide bulk and also to yield amatrix material having the desired level of stickiness. One suchadmixture is glycerin, which is easily mixed with carboxypolymethylene.Another optional component is water, as set forth above. It ispreferable to use a base in order to adjust the pH of the matrixmaterial. Preferred bases can include inorganic bases such as sodiumhydroxide or ammonium hydroxide. Alternatively, the base may include anorganic base such as triethanolamine or other organic amines.

Because the compositions and methods of the present invention aredirected to desensitizing a person's teeth, a suitable desensitizingagent is dispersed within the matrix material in order to contact theperson's tooth surfaces over a desired period of time. Examples ofpreferred desensitizing agents within the scope of the present inventioninclude potassium nitrate (KNO₃), citric acid, citric acid salts,strontium chloride, and the like. Since desensitizing agents mustpenetrate into the pores of a person's teeth in order to reach thenerves within the dental pulp, the sticky compositions of the presentinvention allow for prolonged contact between the dental agent and theperson's teeth.

In addition to potassium nitrate, other dental agents can be added toprovide other useful properties or activities to the dentalcompositions. For example, fluoride salts can be added in order to addan anticariogenic property to the tooth desensitizing compositions.Peroxides can also be added in order to provide a disinfecting actionand/or provide bleaching of stained teeth. Since peroxides are known tocause irritation and also greater sensitivity in teeth, the simultaneousinclusion of a desensitizing agent can offset the negative effects ofthe peroxide. Examples of preferred antimicrobial agents that can beadded to fight gum diseases include chlorhexadine, tetracycline, cetylpyridinium chloride, benzalkonium chloride, cetyl pyridinium bromide,methyl benzoate, and propyl benzoate.

The desensitizing dental compositions within the scope of the presentinvention are sufficiently sticky and generally viscous such thatpositive pressure is needed to dispense them from the container; gravityis not sufficient. Unlike conventional low-viscosity compositions suchas GLY-OXIDE (manufactured by Marion Laboratories) or PROXIGEL(manufactured by Reed and Carnick according to U.S. Pat. No. 3,657,413to Rosenthal), the desensitizing dental compositions of the presentinvention cannot be dispensed drop-wise from a bottle. A syringe,squeezable tube, or other similar positive pressure dispensing device isneeded to dispense the dental compositions within the scope of thepresent invention.

An improved dental tray that is thin-walled, flexible and lightweightfor holding the dental composition adjacent to a person's teeth ispreferably used in combination with the desensitizing dentalcompositions of the present invention. The general process for preparingsuch dental trays is as follows. First, an alginate impression whichregisters all teeth surfaces plus the gingival margin is made and astone cast is made of the impression. Optional reservoirs can beprepared by building a layer of rigid material on the stone cast onspecific teeth surfaces to be treated. A dental tray is then vacuumformed from the modified cast using a thin, flexible membrane material.Once formed, the tray is preferably trimmed barely shy of the gingivalmargin on both the buccal and lingual surfaces of the person's teeth.The resulting tray provides a perfect fit of the person's teeth withoptional reservoirs or spaces located where the rigid material wasplaced on the stone cast. The trays can optionally overlap the gums ifdesired to provide contact between the dental compositions and aperson's gums. The trays of the present invention have greatly increasedcomfort and exert little or no significant mechanical pressure on aperson's teeth or gums. Instead, the sticky dental compositions act likea glue to hold the inventive trays in place.

The amount of tooth desensitization obtained during use of the inventivecompositions and methods is dependent upon (1) the length of time eachday the tray is worn; (2) the number of days the tray is worn; and (3)the susceptibility of the teeth to the desensitizing agent. Thetreatment schedule may be tailored to each person's lifestyle orresponse to the treatment and can be performed as often as a persondesires to provide effective relief from sensitive teeth. It has beenfound that treatment during sleep is a good treatment time of the daysince less mouth activity will pump the bleaching composition from thetray.

Accordingly, an object of the present invention is to providecompositions and methods for treating sensitive teeth that can providetreatment more frequently than during dental visits.

Additionally, it is an object of the present invention to provideimproved compositions and methods for treating sensitive teeth which canbe used frequently but which provide prolonged treatment for an extendedperiod of time compared to conventional desensitizing toothpastes.

It is a further object and feature of the present invention to providecompositions and methods for treating sensitive teeth which allow moreof the desensitizing agent to permeate into the pores and/or fissureswithin a person's teeth in order to provide greater desensitization.

It is a further object of the present invention to provide dentalcompositions and methods for treating sensitive teeth that can beadapted for use by disabled or semi-debilitated people who may not havethe strength, coordination, or ability to brush their teeth without theassistance of others.

It is another object to provide compositions for treating sensitiveteeth which can optionally include other dental agents, such asantimicrobial agents or anticariogenic agents, for treating other toothand/or gum ailments.

Finally, it is an object and feature of this invention to providecompositions for treating sensitive teeth that are sufficiently stickyand resistant to dilution by saliva such that they have the ability toadhere and retain a flexible, thin-walled dental tray against a person'steeth, wherein the dental tray does not exert significant mechanicalpressures onto the person's teeth or gums.

These and other objects and features of the present invention willbecome more fully apparent from the description as follows, or may belearned by the practice of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a stone cast of a patient's teeth with arigid coating being applied to selected teeth surfaces.

FIG. 2 is a perspective view of the stone cast of FIG. 1 with a dentaltray formed from the cast and trimmed below the gingival margin.

FIG. 3 is a cross-sectional view taken along line 3--3 of FIG. 2.

FIG. 3A is an enlarged close-up view taken within the section line3A--3A of FIG. 3.

FIG. 4 is a cross-sectional view taken along line 4--4 of FIG. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As summarized above, the present invention generally relates to sticky,glue-like dental compositions and methods for treating sensitive teeth.Such compositions are preferably used in conjunction with improveddental trays that are preferably thin-walled, flexible, and lightweightfor holding the dental composition adjacent the person's tooth surfaces.Such trays exert little or no significant mechanical pressure onto theperson's teeth and/or gums, which makes them more comfortable andpleasant to use compared to other dental trays. It is the glue-likeaction of the dental compositions that adheres and retains the tray to aperson's teeth. Prior dental treatments that employed a dental tray haveemployed non-viscous, non-sticky liquids that rely on the mechanicalpressure of the tray to hold and retain the tray against the person'steeth.

The inventive dental compositions include a desensitizing agent that isdispersed within a sticky matrix material. Suitable sticky matrixmaterials are preferably safe for oral use, do not readily dissolve insaliva, and do not react with or inactivate the desensitizing agent. Onecurrently preferred sticky matrix material includes carboxypolymethylenetogether with other suitable admixtures. Carboxypolymethylene is a broadterm that refers to vinyl polymers having active carboxyl groups.Suitable carboxypolymethylene compositions may be obtained from B. F.Goodrich Company under the tradename "CARBOPOL". Another tradename forcarboxypolymethylene is CARBOMER. In its non-neutralized form,carboxypolymethylene can have a pH as low as 2.5. As discussed below,the pH of carboxypolymethylene can be raised to yieldcarboxypolymethylene in a neutralized or partially neutralized state.

The amount of carboxypolymethylene within the inventive dentalcompositions can vary depending on the desired level of stickiness andalso the identities and amounts of the other components within thedental composition. With the understanding that it is the concept ofstickiness or adhesive ability that is the important feature of thecompositions of the present invention, one of ordinary skill in the artcan alter the concentrations of the various components to yield dentalcompositions that are able to exert an adhesive force sufficient toreliably adhere and maintain a dental tray against a person's teethwithout significant mechanical pressure being exerted by the dentaltray. In general, the dental compositions of the present invention willpreferably include carboxypolymethylene in a concentration in a rangefrom about 0.5% to about 20% by weight of the dental composition, morepreferably in a range from about 2% to about 12% and most preferably ina range from about 3% to about 10%.

It should be understood that the actual amount of carboxypolymethyleneis not critical. The important thing is that the composition have therequired amount of stickiness and adhesive ability. The matrix materialmay include other tackifying components that in combination with, or inlieu of some or all of, the carboxypolymethylene will yield a dentalcomposition having the desired level of stickiness needed to hold adental tray in place over a person's teeth. Other synthetic polymersand/or natural gums, proteins, or other gel-forming admixtures can beused so long as they yield a sticky dental composition.

One currently preferred carboxypolymethylene resin is known by thetradename CARBOPOL 934P. CARBOPOL 934P is a high purity pharmaceuticalgrade of CARBOPOL 934, having an approximate molecular weight of about3,000,000. In addition to thickening, suspending, and emulsifying,CARBOPOL 934P has been used in dry tablets to impart sustained releaseproperties. Extensive toxicity studies have been conducted on CARBOPOL934P, and a master file has been established with the Food and DrugAdministration. It is listed as CARBOMER 934P in the National Formulary.A more recently preferred carboxypolymethylene is CARBOPOL 974P NF,which has more recently surpassed CARBOPOL 934P as thecarboxypolymethylene of choice. Although CARBOPOL 974P NF is similar oridentical in molecular weight compared to CARBOPOL 934P, it is purifiedin a way that makes it more pharmaceutically acceptable material.

It is believed that other carboxypolymethylene resins, such as CARBOPOL940, may be substituted for CARBOPOL 934P or CARBOPOL 974P NF. However,based upon clinical and laboratory evaluations, it has been found thatCARBOPOL 940 dilutes faster than either CARBOPOL 934P or CARBOPOL 974PNF. In addition, CARBOPOL 934P and CARBOPOL 974P NF are currentlypreferred because they are obtainable in a pharmaceutical grade. It wasthe inventor that first discovered that carboxypolymethylene can be usedto form a glue-like dental composition that can be used as an adhesiveto hold a dental tray against a person's teeth, which has eliminated theneed to use dental trays that are self-retaining, i.e., which exertenough mechanical pressure onto a person's teeth and/or gums such thatthey will be reliably retained in place over a person's teeth for adesired period of time.

The sticky dental compositions within the scope of the present inventionhave a number of important characteristics in addition to stickiness andhigh viscosity. They are also resistant to dilution by saliva such thata significant quantity of saliva or water is required to lower theviscosity to the point that the dental composition may be diluted andwashed out by salivating action. Because the carboxypolymethylenereduces the risk of dilution from saliva and increases the time forsalivary dilution, the resulting dental compositions are able to provideprolonged exposure of the teeth to the dental agent within the dentalcomposition. In addition, the stickiness of the compositions ensuresgood contact between the composition and the person's teeth.

In order to obtain good dispersion of the carboxypolymethylene resinwithin the dental composition, it is recommended that thecarboxypolymethylene be mixed with a quantity of glycerine, otherpolyol, or like substance before attempting to add other components thatare less compatible with carboxypolymethylene, such as water. Glycerineappears to enable larger quantities of carboxypolymethylene to bedispersed in water. It has also been observed that once thecarboxypolymethylene and glycerine have been mixed, it is preferable toquickly disperse the resulting mixture in the water or else it canstiffen to the point where addition of water becomes impracticable. Itis preferable that the concentration of glycerine, polyol, or likesubstance in the dental compositions of the present invention be in arange from about 20% to about 85% by weight of the dental compositions,more preferably in a range from about 30% to about 70% by weight.

Glycerine, other polyols, and the like are inexpensive fillers that workwell in forming a sticky gel with carboxypolymethylene. Becauseglycerine is hydrophilic, it can act as an emulsifying agent if water isused. The glycerine also provides some flavor enhancement such that abland, sweet flavor is perceived. A few possible substitutes forglycerine include propylene glycol, polypropylene glycols, sorbitol,polyethylene glycols, other polyols, and the like. Ethylene glycol wouldalso work but is disfavored since it can be toxic if ingested in largeenough amounts.

Water may also be included within the compositions of the presentinvention, although more carboxypolymethylene must generally be added aswater is added to maintain the same level of stickiness. The amount ofwater included within the dental compositions of the present inventionis preferably in a range from about 0% to about 50% by weight of thedental composition, more preferably in a range from about 2% to about30% by weight. It will be appreciated that the total quantity of waterin the dental composition may come from different sources. For instance,some dental agents and bases, discussed below, may come as aqueoussolutions.

Because carboxypolymethylene is a polycarboxylic acid, it tends to lowerthe pH of the resulting dental compositions significantly, down to a pHof about 2-5 in some cases. It appears, based upon clinical and in vitrotesting, that dental compositions with a pH below about 5 are able toetch enamel. To avoid etching enamel, it is preferable to add a base inorder to raise the pH of the inventive dental compositions to within apH range of about 4 to about 9, more preferably to within a range fromabout 5 to about 7. Inorganic and organic bases may be used, with theuse of concentrated aqueous sodium hydroxide (50% NaOH in water) beingone currently preferred embodiment. Organic bases, such astriethanolamine or other amines can be used. The amount of base to beincluded will generally depend on the desired pH and the amount ofcarboxypolymethylene in the dental composition. Accordingly, bases willpreferably be included in a range from about 1% to about 12% by weightof the dental composition.

The term "carboxypolymethylene" shall be understood to includecarboxypolymethylene resins at any pH, whether neutralized, partiallyneutralized or non-neutralized. The term shall also includecarboxypolymethylene resins that have reacted with, formed complexeswith, or otherwise been altered in any way by other components withinthe dental compositions of the present invention so long as thecarboxypolymethylene is able to impart the desired level of stickinessto the final dental composition in combination with the other componentswithin the dental composition.

Preferred tooth desensitizing agents according to the present inventioninclude potassium nitrate, citric acid, citric acid salts, strontiumchloride, and the like. The amount of desensitizing agent that will beincluded within the dental compositions of the present invention mayvary according to the desired strength and intended treatment times.Accordingly, the desensitizing agent will preferably be included in anamount in a range from about 0.1% to about 10% by weight of the dentalcomposition, more preferably in a range from about 1 to about 7% byweight. Other desensitizing agents are certainly within the scope of thepresent invention and their concentration can be adjusted by those ofordinary skill in the art to provide appropriate relief from sensitiveteeth. The sticky dental compositions of the present invention canensure good contact between the desensitizing agent and a person's teethfor extended periods of time.

In addition to the desensitizing agent, it may be preferable to includeother active dental agents to provide other types of dental and/or gumtreatment. For example, in conjunction with dental desensitization, itmay be desired to provide an anticariogenic treatment. Preferredanticariogenic agents include fluoride salts, more particularly sodiummonofluorophosphate, sodium fluoride, and stannous fluoride. Dependingon the level of fluoride treatment desired, and depending on whether ornot a composition is "over-the-counter" or "by prescription", thefluoride will be included in a range from about 0% to about 1% by weightof the dental composition, more preferably in a range from about 0.1% toabout 0.5% by weight. Presently, a sodium monofluorophosphate level of0.15% by weight is the highest allowable level of fluoride withinnon-prescription dental compositions, or 0.11% is NaF is used.Typically, 0.5% fluoride is the prescription level, assuming the use ofsodium monofluorophosphate.

Antimicrobial agents, e.g., for fighting gum disease, may be included inconjunction with the potassium nitrate or other desensitizing agent.Examples of useful antimicrobial agents include chlorhexadine,tetracycline, cetyl pyridinium chloride, benzalkonium chloride, cetylpyridinium bromide, methyl benzoate, and propyl benzoate. Theantimicrobial agents are preferably included in an amount in a rangefrom about 0% to about 15% with the dental composition, more preferablyin a range from about 1% to about 5% by weight.

In order to preserve the stability of the dental compositions, it isoften preferable to include an ion scavenger such as EDTA, salts ofEDTA, citric acid, succinic acid, and adipic acid, which arecommonly-used chelating agents. Ion scavengers are preferably includedin an amount in a range from about 0% to about 1% by weight of thedental composition, more preferably in a range from about 0.01% to about0.5% by weight.

Finally, although most peroxides such as hydrogen peroxide and carbamideperoxide have been found to be unstable in the presence of potassiumnitrate, it may be possible to add peroxide to the dental compositionsof the present invention shortly before treatment in order to combinethe bleaching and/or antiseptic action of the peroxide with thedesensitization action of the potassium nitrate. In the event that astabilizing agent could be found that would make peroxides and potassiumnitrate stable when mixed together without diminishing the effects ofthe potassium nitrate, such a combination certainly would becontemplated by the present invention.

An important characteristic of the sticky dental compositions within thescope of the present invention is that the compositions can still beobserved, from a clinical standpoint, after about 3 to 7 hours of normaldaytime activity and after about 7 to 10 hours of sleep. That is, thesticky, high viscosity dental composition is still observable in thedental tray after an extended period of time, such as at the end of thenight, due to their ability to retain the dental tray firmly in placewhile the treatment regimen is in progress.

Unlike existing low-viscosity compositions, such as PROXYGEL, which areplaced drop-by-drop into the tray, the dental compositions within thescope of the present invention have a viscosity such that they cannot bedispensed drop-wise into a dental tray from a bottle. Positive pressureis needed to expel the dental compositions of the present invention fromthe container; gravity is not sufficient.

One currently preferred method of dispensing the inventive dentalcompositions is by means of a syringe. Squeezable tubes and othersimilar dispensing devices may also be used to dispense thecompositions. Upon dispensing, the dental compositions are sufficientlyviscous that they do not easily settle or spread once dispensed, butwill generally remain as a single extruded strand or bead of dentalcomposition.

It is currently preferred to provide a unit dose of the dentalcompositions in a syringe or similar dispensing device. In this way, theperson can load the precise amount of dental composition onto the dentaltray for each treatment period. By using such dispensing devices, thedentist is also able to monitor how many doses the person has receivedand used.

Although not required, the dental compositions of the present inventionare preferably used to treat a person's teeth in conjunction with dentaltrays that exert little or no significant mechanical pressure onto aperson's teeth and gums. The result is a more comfortable and pleasantfeeling dental tray, unlike prior art dental trays which are generallyrigid and/or thick-walled such that they exert sufficient mechanicalpressures onto the teeth and/or gums to be "self-retaining". That is,prior dental trays can be used with dental compositions which areneither sticky nor viscous since the compositions are not relied upon toadhere and retain the self-retaining prior art dental trays. Incontrast, preferred dental trays used according to the present inventionexert little if any significant mechanical pressure onto a person'steeth and/or gums.

In the general process for preparing the dental trays according to thepresent invention, an alginate impression is made which registers allteeth surfaces plus the gingival margin. Thereafter, a stone cast ismade of the impression. Excess stone can be trimmed away for easymanipulation and forming the dental tray.

Reference is now made to FIGS. 1-4. In a preferred method for forming adental tray, one or more reservoirs can be formed in the resultantdental tray by applying a thin coating 10 of a rigid material to thestone cast 12 corresponding to teeth where it is desired to provide moreof the dental composition. As depicted in FIG. 1, the coating 10 may beapplied using a brush tipped applicator 14. The coating may also belight curable for convenience. In those instances where the dental trayis to be trimmed below the gingival margin, the coating material willpreferably be applied in a manner that is kept at a distance greaterthan about 1 mm from the gingival line 16, more preferably in a rangefrom about 1.25 to about 1.5 mm from the gingival line 16.

The finished coating will have a thickness corresponding to the desiredreservoir depth, which will commonly be about 0.5 mm. It is generallypreferred that the rigid coating material not be applied over the stonecast corresponding to the incisal edges 18 and occlusal edges 20 of theperson's teeth. This because it is preferable for the incisal edges andocclusal edges of the person's actual teeth to contact the finished trayin order to prevent or reduce vertical movement of the tray during use,which movement could act as a pump that could express the dentalcomposition from the tray and result in the intake of saliva within thedental tray.

A dental tray 22 is then vacuum formed from the stone cast usingconventional techniques. The dental tray 22 is preferably constructed ofa soft transparent vinyl material preferably having a preformedthickness in a range from about 0.5 mm to about 2 mm, more preferably ina range from about 1 mm to about 1.5 mm. Soft materials yield dentaltrays that are more comfortable for the patient to wear. It will beappreciated that the final tray thickness may vary depending on thetechnique used to prepare the tray, as well as the size and shape of theperson's teeth. Patients suspected of being breuxers or hard biters mayrequire either a thicker or a harder material. Of course, patientsshould be counselled not to eat with trays in place or to bite firmlyinto them.

Once formed, the dental tray 22 is preferably trimmed barely shy of thegingival margin 16 of the person's teeth on both the buccal and lingualsurfaces for maximum comfort. Enough tray material should be left toassure that the teeth will be covered to within about 1/4 mm to about1/3 mm of the gingival border upon finishing and beveling of the trayperiphery. It is also generally preferred to scallop up and around theinterdental papilla so that the finished tray does not cover them. Thetray edges are preferably smoothed so that the lip and tongue will notfeel an edge prominence. Slight adjustments to the tray may be made bycarefully heating and stretching the tray material.

From practice, it has been found that patients may experience less toothdiscomfort from tray pressures when using a tray with reservoirs builtinto the tray as described above. It is currently believed this is dueto the fact that the teeth are not held as firmly by the tray, so"orthodontic" pressures experienced by teeth from tray discrepancies areminimized. The use of thin, soft tray materials further minimizes these"orthodontic" forces, compared to the harder plastics currently used inthe art, such as those described in U.S. Pat. No. Re 34,196 to Munro.Reservoirs, of course, provide more of the dental composition to theperson's teeth corresponding to the reservoirs.

Although the aforementioned thin, flexible dental trays are preferredwhen treating a person's teeth, it may be preferable in some cases toallow the dental tray to overlap the person's gums in the case wheredental agents are included to fight gum diseases. Of course, to theextent that the dental compositions do not irritate the gums, the dentaltrays can always be constructed to overlap the gums.

Nevertheless, it has been found that where it is desired to treat aperson's teeth rather than the gums, it is generally more comfortablefor the patient if the dental tray has been trimmed to or below thegingival margin. Even in those cases where the dental trays will overlapthe person's gums, the dental trays of the present invention preferablywill not exert significant mechanical pressure onto the person's gums.Contrast this with the prior dental trays according to U.S. Pat. No. Re34,196 to Munro, which specifically teach the formation of a"liquid-type seal" between the rigid dental trays and the person's gums.The purpose for this, of course, is that Munro expressly teaches the useof PROXIGEL, which is not sufficiently sticky to reliably retain andhold a dental tray that exerts no significant mechanical pressureagainst a person's teeth and/or gums for long durations.

Because the dental trays made according to the present invention exertlittle or no mechanical pressure onto a person's teeth and gums, it isimportant that the inventive dental compositions be able to act a glueto reliably adhere and retain the dental tray over a person's teeth forthe desired length of treatment. Accordingly, the dental compositionswill preferably have a stickiness such that they can reliable adhere andretain a dental tray over a person's teeth for at least about one hourwithout significant mechanical pressure from the dental tray, morepreferably for at least about two hours, and most preferably for atleast about four hours. Nevertheless, while the foregoing time durationsare given in order to provide an accurate measurement of the stickinessof the dental compositions of the present invention, they should not betaken to be a limitation as to the actual length of time that thepatient may wish to use the inventive dental compositions. While a givendental composition may be able to retain the dental tray against aperson's teeth for, e.g., 10 hours or more, that composition couldcertainly be used for 15 minutes, one hour, or for any desired timeduration.

Although the use of flexible, thin-walled dental trays is certainlypreferred, it is within the scope of the present invention to use theinventive sticky dental compositions with conventional trays. Theincreased adhesive action of the inventive dental compositions willensure a more reliable mechanical and chemical contact between theactive dental agents and the person's teeth regardless of the type ofdental tray that is used. Nevertheless, it is preferable to use theinventive dental trays since they are clearly more comfortable to usecompared to prior dental trays that mechanically lock themselves over aperson's teeth and/or gums in a kind of press-fit arrangement.

The dental compositions of the present invention may be used at any timeand for any duration by a person that is experiencing sensitive teeth.Although the dental compositions of the present invention facilitate theuse of flexible, thin-walled dental trays that are more comfortable touse compared to prior dental trays, the insertion of any dental traywithin a person's mouth will cause some alteration of behavior anddiminution of the freedom to use one's mouth. Therefore, in order tomaximize treatment time and reduce the inconvenience of having a dentaltray lodged within a person's mouth, it is recommended to use the dentaltrays at night during a person's sleep.

Typical treatment times for night use will range from between 5 to 10hours depending on the length a person remains in bed. For day use, thedesensitizing dental compositions of the present invention have beenfound to provide some relief for treatment times as little as 15minutes, although treatment times of one to three hours are recommended.

Regardless of which treatment schedule is used, the use of the stickydental compositions within the scope of the present invention provides amore constant level of desensitizing activity compared to home-usecompositions, such as toothpaste. Since the amount and length of timethe active desensitizing agent is adjacent the teeth significantlyinfluences the efficiency of the treatment, the sticky bleachingcompositions and methods of the present invention represent asignificant improvement over existing home-use tooth desensitizingsystems.

In order to more clearly illustrate the parameters of the inventivedental compositions within the scope of the present invention, thefollowing examples are presented. The following examples are intended tobe exemplary and should not be viewed as limiting to the scope of theinvention.

EXAMPLE 1

A sticky tooth desensitizing dental composition within the scope of thepresent invention was prepared by combining the following ingredients inthe following proportions:

    ______________________________________                                        Water                   20%                                                   KNO.sub.3               2%                                                    CARBOPOL 974P NF        4%                                                    Sodium hydroxide (50%)  5.4%                                                  Disodium EDTA           0.1%                                                  NaF                     0.11%                                                 Glycerine               68.4%                                                 ______________________________________                                    

The CARBOPOL 974P NF was obtained from B.F. Goodrich Company inCleveland, Ohio. The CARBOPOL 974P NF was first combined with theglycerine and then mixed with the water. The glycerine enabled theCARBOPOL 974P NF to be more easily mixed with the water. The KNO₃ anddisodium EDTA were added to the mixture, after which the sodiumhydroxide was blended into the homogeneous composition in order to raisethe pH to an acceptable level. The resulting dental composition had bothdesensitizing and anticariogenic properties, and was sufficiently stickythat it could reliably hold and maintain a dental tray against aperson's teeth without significant mechanical pressure being exerted bythe tray onto a person's teeth and gums.

EXAMPLE 2

A sticky desensitizing dental composition within the scope of thepresent invention was made according to the procedure of Example 1,except that the water was excluded such that the remaining componentswere combined in the following amounts:

    ______________________________________                                        KNO.sub.3               2%                                                    CARBOPOL 974P NF        2.5%                                                  Disodium EDTA           0.1%                                                  Sodium fluoride (NaF)   0.11%                                                 Sodium hydroxide (50%)  5.4%                                                  Glycerine               89.9%                                                 ______________________________________                                    

The foregoing procedure resulted in a sticky dental composition. Theresulting dental composition had both desensitizing and anticariogenicproperties, and was sufficiently sticky that it could reliably hold andmaintain a dental tray against a person's teeth without significantmechanical pressure on the patient's teeth and gums.

EXAMPLE 3

A dental composition within the scope of the present invention is madeaccording to the procedure of Example 1, except that the ingredients arecombined in the following concentrations by weight %:

    ______________________________________                                        KNO.sub.3               0.5%                                                  Water                   20                                                    Glycerine               63.6%                                                 CARBOPOL 974P NF        7%                                                    Sodium hydroxide (50%)  9.4%                                                  ______________________________________                                    

The foregoing procedure results in a sticky dental composition havingreduced but significant desensitizing activity.

EXAMPLE 4

A dental composition within the scope of the present invention is madeaccording to the procedure of Example 1, except that the ingredients arecombined in the following concentrations by weight %:

    ______________________________________                                        KNO.sub.3               1%                                                    Water                   10%                                                   Polyethylene glycol     80.8%                                                 CARBOPOL 974P NF        3.5%                                                  Sodium hydroxide (50%)  4.7%                                                  ______________________________________                                    

The foregoing procedure results in a sticky dental composition havingreduced but significant desensitizing activity.

EXAMPLE 5

A dental composition within the scope of the present invention is madeaccording to the procedure of Example 1, except that the ingredients arecombined in the following concentration by weight %:

    ______________________________________                                        KNO.sub.3               7%                                                    Water                   30%                                                   Propylene glycol        46.6%                                                 CARBOPOL 974P NF        7%                                                    Sodium hydroxide (50%)  9.4%                                                  ______________________________________                                    

The foregoing procedure results in a sticky dental composition having ahigh level of desensitizing activity.

EXAMPLE 6

A dental composition within the scope of the present invention is madeaccording to the procedure of Example 1, except that the ingredients arecombined in the following concentrations by weight %:

    ______________________________________                                        KNO.sub.3               10%                                                   Water                   15%                                                   Sorbitol                65.6%                                                 CARBOPOL 974P NF        4%                                                    Sodium hydroxide (50%)  5.4%                                                  ______________________________________                                    

The foregoing procedure results in a sticky dental composition having ahigh level of desensitizing activity.

EXAMPLE 7

A dental composition within the scope of the present invention is madeaccording to the procedure of Example 1, except that the ingredients arecombined in the following concentrations by weight %:

    ______________________________________                                        KNO.sub.3              5%                                                     Water                  5%                                                     Polypropylene glycol   77.7%                                                  CARBOPOL 974P NF       5%                                                     Sodium hydroxide       6.7%                                                   Sodium BDTA            0.5%                                                   NaF                    0.11%                                                  ______________________________________                                    

The foregoing procedure results in a sticky dental composition having amoderate to high level of desensitization activity and a high level ofanticariogenic activity.

EXAMPLE 8

A dental composition within the scope of the present invention is madeaccording to the procedure of Example 1, except that the ingredients arecombined in the following concentrations by weight %:

    ______________________________________                                        KNO.sub.3              2%                                                     Glycerine              92.9%                                                  CARBOPOL 974P NF       3%                                                     Triethanolamine        2%                                                     Disodium EDTA          0.1%                                                   ______________________________________                                    

The foregoing procedure results in a sticky dental composition that iscombined with urea peroxide (10 wt %) just prior to treatment to yield adental composition having bleaching activity as well as desensitizingactivity.

EXAMPLE 9

To any of the foregoing dental compositions is added one or more of thefollowing antimicrobial agents for treatment of a patient's gums:chlorhexadine, tetracycline, cetyl pyridinium chloride, benzalkoniumchloride, cetyl pyridinium bromide, methyl benzoate, and propylbenzoate. These compositions are preferably used in conjunction with athin walled, flexible dental tray that overlaps the person's gums inorder for the dental compositions to contact the gums being treated.

EXAMPLE 10

To any of the foregoing dental compositions is added one of thefollowing chelating agents: EDTA, monosodium EDTA, citric acid, succinicacid, and adipic acid.

In some cases, the sticky dental compositions may be used without adental tray. For example, a sticky dental composition having anantimicrobial agent may be expressed directly into periodontal pockets.In such compositions, it would be preferred to maximize thecarboxypolymethylene concentration and minimize the amount of addedwater so that the effects of saliva dilution are minimized. In addition,mucosal adhesive materials may be added to the composition to furtherassist in retaining the composition within the periodontal pocket. Theprolonged activity of the dental agent within the sticky gel may lastfrom hours to days, depending on the patient's oral and salivalactivity.

From the foregoing, it will be appreciated that the present inventionprovides compositions and methods for treating sensitive teeth that canprovide treatment more frequently than during dental visits.

Additionally, it will be appreciated that the present invention furtherprovides improved compositions and methods for treating sensitive teethwhich can be used frequently and which provide prolonged treatment foran extended period of time compared to conventional desensitizingtoothpastes.

It will further be appreciated that the present invention providescompositions and methods for treating sensitive teeth which allow moreof the desensitizing agent to permeate into the pores and/or fissureswithin a person's teeth in order to provide greater desensitization.

Further, the present invention provides dental compositions and methodsfor treating sensitive teeth that can be adapted for use by disabled orsemidebilitated people who may not have the strength, coordination,ability to brush their teeth without the assistance of others.

The present invention also provides dental compositions for treatingsensitive teeth which optionally include other dental agents fortreating teeth and/or gums, such as antimicrobial or anticariogenicagents.

Finally, the present invention provides compositions for treatingsensitive teeth that are sufficiently sticky and resistant to dilutionby saliva such that they have the ability to adhere and retain aflexible, thin-walled dental tray against a person's teeth, wherein thedental tray does not exert significant mechanical pressures onto theperson's teeth or gums.

The present invention may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the invention is, therefore, indicatedby the appended claims rather than by the foregoing description. Allchanges which come within the meaning and range of equivalency of theclaims are to be embraced within their scope.

What is claimed and desired to be secured by United States LettersPatent is:
 1. A sticky dental composition adapted for use with a dentaltray for treating sensitive teeth comprising:a desensitizing agent forreducing dental pain sensations; and a tackifying agent selected fromthe group consisting of carboxypolymethylene, gums, proteins, andmixtures thereof, the dental composition having a stickiness so that thedental composition is capable of adhering and retaining a dental trayover a person's teeth for at least about one hour, wherein the dentaltray is designed not to exert mechanical pressure onto the person'steeth and gums.
 2. A sticky dental composition as defined in claim 1,wherein the desensitizing agent includes potassium nitrate.
 3. A stickydental composition as defined in claim 1, wherein the desensitizingagent is selected from the group consisting of citric acid, citric acidsalts, and strontium chloride.
 4. A sticky dental composition as definedin claim 1, wherein the desensitizing agent is included in amount inrange from about 0.1% to about 10% by weight of the dental composition.5. A sticky dental composition as defined in claim 1, wherein thedesensitizing agent is included in amount in range from about 1 to about7% by weight of the dental composition.
 6. A sticky dental compositionas defined in claim 1, wherein the tackifying agent includescarboxypolymethylene.
 7. A sticky dental composition as defined in claim6, wherein the carboxypolymethylene is included in an amount in a rangefrom about 0.5% to about 20% by weight of the dental composition.
 8. Asticky dental composition as defined in claim 6, wherein thecarboxypolymethylene is included in an amount in a range from about 2%to about 12% by weight of the dental composition.
 9. A sticky dentalcomposition as defined in claim 6, wherein the carboxypolymethylene isincluded in an amount in a range from about 3% to about 10% by weight ofthe dental composition.
 10. A sticky dental composition as defined inclaim 1, further including water in an amount up to about 50% by weightof the dental composition.
 11. A sticky dental composition as defined inclaim 10, wherein the water is included in an amount in a range fromabout 2% to about 30% by weight of the dental composition.
 12. A stickydental composition as defined in claim 1, further including a polyol.13. A sticky dental composition as defined in claim 1, further includinga base present in an amount so that the dental composition has a pH in arange from about 4 to about
 9. 14. A sticky dental composition asdefined in claim 13, wherein the pH is in a range from about 5 to about7.
 15. A sticky dental composition as defined in claim 1, furtherincluding an antimicrobial agent selected from the group consisting ofchlorhexadine, tetracycline, cetyl pyridinium chloride, benzalkoniumchloride, cetyl pyridinium bromide, methyl benzoate, and propylbenzoate.
 16. A sticky dental composition as defined in claim 1, furtherincluding an anticariogenic agent selected from the group consisting ofsodium monofluorophosphate, sodium fluoride, and stannous fluoride. 17.A sticky dental composition as defined in claim 1, wherein the dentalcomposition is pre-loaded within a syringe.
 18. A sticky dentalcomposition adapted for use with a flexible, thin-walled dental tray fortreating sensitive teeth comprising:a desensitizing agent for reducingdental pain sensations; and a tackifying agent comprisingcarboxypolymethylene included in an amount within the dental compositionin order that the dental composition has a stickiness and resistance todilution by saliva so that the dental composition is capable of adheringand retaining a dental tray over a person's teeth for at least about onehour, wherein the dental tray is designed so as not to exert mechanicalpressure onto the person's teeth and gums, the carboxypolymethylenebeing neutralized in order that the resulting dental composition has apH in a range from about 4 to about
 9. 19. A sticky dental compositionas defined in claim 18, wherein the carboxypolymethylene is added in anamount in a range from about 2% to about 12% by weight of the dentalcomposition.
 20. A sticky dental composition for treating sensitiveteeth in combination with a flexible, thin-walled dental tray that isdesigned not to exert mechanical pressure onto a person's teeth andgums, the dental composition comprising:a desensitizing agent forreducing dental pain sensations; and a matrix into which thedesensitizing agent is dispersed, the matrix including a tackifyingagent selected from the group consisting of carboxypolymethylene, gum,proteins, and mixtures thereof, a polyol, a base, and optionally water,the dental composition having a stickiness and resistance to dilution bysaliva so that the dental composition is capable of adhering andretaining the dental tray over a person's teeth for at least about onehour, the dental composition being neutralized to a pH in a range fromabout 5 to about
 7. 21. A sticky dental composition as defined in claim1, further including a bleaching agent.
 22. A sticky dental compositionas defined in claim 18, further including a bleaching agent.
 23. Asticky dental composition as defined in claim 20, further including ableaching agent.